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kravi Meguiar's D12001 Glass Cleaner Concentrate 1 gallon. Dilutes 10-1 with distilled water, gives you a TON of glass cleaner to work with. Keep your old bottles of windex or invisible glass to use this with.
Also use with an Invisible Glass Reach And Clean tool, and get a 3-pack of the bonnets. This will allow you to buff the inside window without cramping your neck and shoulders.
Also following on what skylinekin was saying, I keep my towels separated in plastic storage bins and hand-wash them after every use. Really important to keep your glass towels free of contamination.